Various devices and methods have been developed in the past for the treatment of horizontal surfaces such as floors. Improving and accelerating floor cleaning operations, particularly by various kinds of automation, have been concerns as long as floors have been cleaned. Because floor-cleaning and similar surface-treating operations are rather labor intensive, substantial cost savings may be available from automation.
With the explosive growth in the use of tack-down carpets in recent years, improving the quality and efficiency of carpet-cleaning operations has become a particular concern. While caring for carpets is generally no more costly than caring for hard floor, carpet care presents a number of unique problems due to the nature of the carpet surface.
For example, a carpeted surface is fibrous, thick and a bit irregular when compared to a flat hard floor; the path of a wheeled device traversing carpet can be affected by these qualities. And, carpet cleaning other than simple vacuuming can involve a number of steps complicating automation.
In the past, a number of devices referred to as "automatic" have been developed for treatment of horizontal surfaces, including in some cases carpets. Many of these devices are "automatic" in the sense that they interact with the surface beneath them without the direct manipulation of brushes, scrubbers, or nozzles by operators, even though operators constantly attend such devices by pushing or guiding them.
Some prior automatic floor-treating devices are "automatic" in the additional sense that they may operate unattended, that is, without an operator beside them to push or otherwise guide them. Among such prior devices are those disclosed in U.S. Pat. Nos. 4,503,581 (Early) and 1,935,158 (Lumley). Such devices traverse the floor under their own power and control. This invention is an improvement in surface-treating equipment of this more fully automatic type, and most specifically an improvement in carpet-cleaning equipment.
Automatic surface-treating equipment of the prior art has a number of problems and shortcomings. More specifically, improved automatic carpet-cleaning equipment is needed.
Automatic carpet-cleaning or floor-cleaning devices typically perform a number of functions as they pass over the carpet or other floor surface to be cleaned. Such functions may include applying a cleaning composition, scrubbing in some manner, and removing the dirt and used cleaning composition.
Such multiple steps may be carried out in a single pass or more then one pass along a first path. After the first path has been treated, it is necessary to repeat the same step or steps along a second path which is parallel to the first path. It is very important that the second path be contiguous with the first path so that there are no neglected strips between the paths.
In particular, there is a tendency for such apparatus to move over a floor in a somewhat erratic or insufficiently controlled manner, particularly when moving from one straight path to the adjacent, or next straight path. Some prior devices have means for lateral movement to a new parallel path. However, such devices are complex in construction and by their nature may be prone to inaccurate movement. Successful treatment of large surface areas without leaving gaps is most difficult. In carpet cleaning operations, it is particularly important that gaps between cleaning paths be avoided.
Some prior automatic unattended devices for treating horizontal surfaces are by their nature suited primarily to use on hard surfaces. The irregularity of carpet surfaces complicates lateral movement. Improved equipment is used for accurate traversing of carpeted surfaces during automatic cleaning operations.
Automatic carpet-cleaning devices, because of the many steps typically necessary as mentioned above, require considerable space for the carpet-cleaning elements and assemblies which must be included. Certain automatic devices of the prior art, because of the apparatus they require for floor-traversing and side-stepping movements, do not provide much space on the for carpet-cleaning elements and assemblies. Improved equipment is needed which provides not only accuracy in movements, including side-stepping movements, but ample room for the elements and assemblies needed for thorough carpet cleaning.
There has been a long-standing need for practical, easily usable and programmable surface-treating apparatus which can dramatically cut labor costs in operations such as carpet cleaning. There is a need for equipment with improved accuracy in its surface-traversing movements even on surfaces such as carpets.